From DE 10 2010 025 170 B4 there is known a method for determining the position of a magnet at a time of measurement relative to a row of sensors extending in a row direction. The position of the magnet relative to the row of sensors can be changed in a direction parallel to the row direction, wherein the row of sensors has a first magnetic-field-sensitive sensor and a second magnetic-field-sensitive sensor, which is arranged, spaced apart from the first sensor in the row direction. In the method known from DE 10 2010 025 170 B4, in one preferred embodiment it is possible for sensors to be employed which are each constructed like the sensor shown in FIGS. 8a), 8b) of DE 10 2010 025 170 B4. Such a sensor has a first part (resistors R1, R2, R3, R4) which generates a first intermediate signal, and a second part (resistors R5, R6, R7, R8) which generates a second intermediate signal, the progression of the first intermediate signal and the progression of the second intermediate signal being dependent on the direction and/or the strength of the magnetic field generated by the magnet at the location of the sensor. The first intermediate signal substantially has a sine-type progression (cf. FIG. 8b) for the applied voltage (U sin)). The second intermediate signal substantially has a cosine-type progression (cf. FIG. 8b) for the applied voltage (U cos)). As can be seen from FIG. 8a, the midpoint of the first part corresponds to the midpoint of the second part. The sine-type and cosine-type signals of the sensor can be used in order to determine the field angle progression. Field angle progression here is understood to mean the progression of the angle which the field direction of a magnetic field, which is generated by a magnet, at the measuring location (at the location of the sensor) assumes relative to a so-called direction of the sensor, such as arises when the magnet passes by the sensor. The direction is a predetermined direction which is meant to simplify the reference. If the field angle is determined at a time of measurement at 30° to the direction, for example, this means that the field direction of the magnetic field generated by the magnet assumes an angle of 30° to the predetermined direction at the measuring location. In the case of the mode of sensor construction known from DE 10 2010 025 170 B4, the field angle emerges in a simple manner through the division of the two signal values, followed by an ArcTangent calculation (field angle=0.5×ARCTAN (Uasin/Uacos)). The embodiment known from DE 10 2010 025 170 B4 additionally offers the advantage that, via the relationship Uasin×Uasin+Uacos×Uacos=constant, it is possible to check, for each individual sensor, whether the sensor signal is correct.
The method proposed in DE 10 2010 025 170 B4 envisions that, in order to determine the position, the sensor signals of a plurality of sensors, in one embodiment the sensor signals of all sensors, of the row of sensors, are evaluated. As depicted in FIG. 1 and FIG. 2 of DE 10 2010 025 170 B4, the method proposed therein is based on generating a sensor signal of the entire device, which sensor signal is composed of the individual measured values of the individual sensors at the time of measurement (FIG. 2). In the method described therein, an examination is then performed regarding by which amount and in which direction the progression of the thus-generated sensor signal of the entire device and the progression of a reference signal have to be displaced relative to one another in order to achieve a congruence between the thus-generated sensor signal of the entire device, and the reference signal. The position of the magnet in which it is situated at the time of measurement is ascertained from the amount and the direction.
A possible disadvantage with the present method can be the calculation effort which has to be employed in order to establish in the evaluation unit the amount by which and the direction in which the progression of the sensor signal and the progression of the reference signal have to be displaced relative to one another in order to achieve congruence between the sensor signal and the reference signal.